Which epithelium lines the stomach and intestines, and what are its notable features?

• A. Stratified squamous epithelium with goblet cells
• B. Simple columnar epithelium with goblet cells and microvilli
• C. Pseudostratified columnar epithelium with cilia
• D. Simple cuboidal epithelium with microvilli

Answer: (B)

The lining of the stomach and intestines is a simple columnar epithelium, a single layer of tall, rectangular cells specialized for secretion and absorption. In this arrangement, goblet cells intersperse among the absorptive cells to produce mucus, which protects and lubricates the lining. In the small intestine, the apical surfaces of these absorptive cells have microvilli, forming a brush border that greatly increases surface area for nutrient absorption. This combination—single, tall cells with mucus-secreting capability and apical microvilli—fits the GI tract’s roles in digestion and absorption. Other epithelial types don’t match these functions: stratified squamous is multi-layered and more about protection, pseudostratified columnar with cilia is typical of the respiratory tract, and simple cuboidal lacks the extensive surface area and mucus-secreting features needed for the stomach and intestines.